Differential lubrication feed system in a drive axle assembly

ABSTRACT

A method for lubricating an axle assembly can include: coupling a pair of tapered roller bearing to opposite ends of a differential housing; placing the differential housing into a carrier housing assembly such that the tapered roller bearings support the differential housing on the carrier housing assembly for rotation about a first axis; collecting a lubricant proximate a side of one of the tapered roller bearings opposite the differential housing; and rotating the differential housing about the first axis to cause the one of the tapered roller bearings to move a portion of the collected lubricant through the differential housing. A related axle assembly is also provided.

INTRODUCTION

The present disclosure generally relates to axle assemblies. Moreparticularly, the present disclosure relates to a method for lubricatinga differential in an axle assembly and a related axle assembly.

U.S. Pat. No. 1,631,217 appears to disclose an oiling system forbearings in a reduction drive. The oiling system employs tapered rollerbearings to pump oil onto the gear teeth of an input pinion; the oil onthe gear teeth is subsequently slung from the gear teeth of the inputpinion where it collects in a chamber that drains toward the taperedroller bearings that support the spur gear (d) of the reduction drive.

U.S. Pat. No. 4,227,427 appears to disclose a drive unit assembly havingan input pinion and a differential. A ring gear associated with thedifferential slings oil onto the tapered roller bearings that supportthe input pinion; a portion of this oil is pumped from these taperedroller bearings to the side and pinion gears of the differential.

SUMMARY

In one form, the present disclosure provides an axle assembly thatincludes a carrier housing, a differential housing, first and secondtapered roller bearings, a gearset, a ring gear, a pinion, a thirdtapered roller bearing and a lubricant. The carrier housing assemblydefines a cavity into which the differential housing is received. Thefirst and second tapered roller bearings are disposed between thecarrier housing and the differential housing and support thedifferential housing for rotation about a first axis. The gearset isreceived in the differential housing. The ring gear is coupled to thedifferential housing. The pinion is received in the cavity. The thirdtapered roller bearing is disposed between the carrier housing and thepinion and supports the pinion for rotation about a second axis that isperpendicular to the first axis. The lubricant is received in thecavity. The carrier housing includes a first lubricant gallery, whichextends from the third tapered roller bearing to a first side of thefirst tapered roller bearing, and a second lubricant gallery thatextends from the third tapered roller bearing to a first side of thesecond tapered roller bearing. The first and second tapered rollerbearings are oriented to receive lubricant from the first and secondlubricant galleries, respectively. The lubricant received by the firsttapered roller bearing is moved through the first tapered roller bearingtoward the second tapered roller bearing when the axle assembly isoperated. The lubricant received by the second tapered roller bearing ismoved through the second tapered roller bearing toward the first taperedroller bearing when the axle assembly is operated.

In another form, the present disclosure provides a method forlubricating differential support bearings in an axle assembly. Themethod includes: providing a carrier housing, a differential housing,first and second tapered roller bearings, a gearset, a ring gear, apinion, and a third tapered roller bearing, the carrier housing assemblythat defining a cavity, the differential housing being received in thecavity, the first and second tapered roller bearings being disposedbetween the carrier housing and the differential housing, the first andsecond tapered roller bearings supporting the differential housing forrotation about a first axis, the gearset being received in thedifferential housing, the ring gear coupled to the differential housing,the pinion received in the cavity, the third tapered roller bearingdisposed between the carrier housing and the pinion and supporting thepinion for rotation about a second axis that is perpendicular to thefirst axis; rotating a portion of the third tapered roller bearingrelative to a remaining portion to pump a lubricant through first andsecond lubricant galleries associated with the carrier housing to supplythe lubricant to the first and second tapered roller bearings,respectively; and rotating a portion of the first and second taperedroller bearings relative to respective remaining portions to pump thelubricant through the first and second tapered roller bearings.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a schematic illustration of a vehicle having an axle assemblyconstructed in accordance with the teachings of the present disclosure;

FIG. 2 is a partially broken-away perspective view of a portion of thevehicle of FIG. 1 illustrating the axle assembly in more detail;

FIG. 3 is a longitudinal sectional view of a portion of the axleassembly;

FIG. 3A is a view similar to that of FIG. 3, but illustrating the secondoil galleries as being fed lubricant from the pinion bearing that isfurthest from the teeth of the pinion;

FIG. 3B is a view similar to that of FIG. 3, but illustrating each ofthe second oil galleries as being fed from a different one of the pinionbearings;

FIG. 4 is a section view taken along the line 4-4 of FIG. 3;

FIG. 5 is a rear elevation view of a portion of another axle assemblyconstructed in accordance with the teachings of the present disclosure;

FIG. 6 is a perspective view of the axle assembly of FIG. 5,illustrating the second oil galleries in more detail;

FIG. 7 is a section view of a portion of another axle assemblyconstructed in accordance with the teachings of the present disclosure,the section being taken through the carrier housing through therotational axis of the input pinion assembly and perpendicular to arotational axis of the differential assembly;

FIG. 8 is a section view of a portion of the axle assembly of FIG. 7taken parallel to the rotational axis of the input pinion assembly andthe rotational axis of the differential assembly.

DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS

With reference to FIG. 1 of the drawings, a vehicle having adifferential assembly that is constructed in accordance with theteachings of the present disclosure is generally indicated by referencenumeral 10. The vehicle 10 can include a driveline 12 that is drivablevia a connection to a power train 14. The power train 14 can include anengine 16 and a transmission 18. The driveline 12 can include apropshaft 20, a rear axle assembly 22 and a plurality of wheels 24. Theengine 16 can be mounted in an in-line or longitudinal orientation alongthe axis of the vehicle 10 and its output can be selectively coupled viaa conventional clutch to the input of the transmission 18 to transmitrotary power (i.e., drive torque) therebetween. The input of thetransmission 18 can be commonly aligned with the output of the engine 16for rotation about a rotary axis. The transmission 18 can also includean output and a gear reduction unit. The gear reduction unit can beoperable for coupling the transmission input to the transmission outputat a predetermined gear speed ratio. The propshaft 20 can be coupled forrotation with the output of the transmission 18. Drive torque can betransmitted through the propshaft 20 to the rear axle assembly 22 whereit can be selectively apportion in a predetermined manner to the leftand right rear wheels 24 a and 24 b, respectively.

With reference to FIG. 2, the rear axle assembly 22 can include an axlehousing assembly 30, a differential assembly 34, an input pinionassembly 36 and a pair of axle shafts 38. The axle housing assembly 30is illustrated to be a Salisbury-type axle housing assembly, but it willbe appreciated that the teachings of the present disclosure haveapplication to other types of axle housing assemblies, includingindependent and banjo axle housing assemblies for front and rear axleassemblies. Moreover, those of ordinary skill in the art will appreciatethat the axle housing assembly 30 could be configured for a front axleor a rear axle as desired. The axle housing assembly 30 can include acarrier housing 54, a pair of bearing caps 56, a pair of axle tubes 58and a cover 60 and can include a lubricant sump or reservoir 62 and afirst oil gallery 64 and a pair of second oil galleries 66.

With additional reference to FIGS. 3 and 4, the carrier housing 54 caninclude a wall member 70 that can define a pair of bearing journals 72,a pair of tube bores 74, a pinion bore 76 and a differential cavity 78.Each of the bearing caps 56 can be coupled (e.g., removably coupled) toan associated one of the bearing journals 72, e.g., via a pair ofthreaded fasteners (not shown). The bearing caps 56 and the bearingjournals 72 can cooperate to define a pair of differential bearingjournals 80 on which the differential assembly 34 may be supported forrotation about a first axis 82. The tube bore 74 can be aligned to thedifferential bearing journals 80 and can be sized to receive the axletubes 58 therein. The pinion bore 76 can intersect the differentialcavity 78 and can extend along a second axis 88 that can be generallyperpendicular to the first axis 82. The cover 60 can be removablycoupled to the carrier housing 54 to close an open end of thedifferential cavity 78. The carrier housing 54 and the cover 60 cancooperate to define the lubricant reservoir 62, and a suitable lubricant90 can be contained therein. The first and second oil galleries 64 and66 can be integrally formed with or coupled to the carrier housing 54.

The differential assembly 34 can be any type of differential and caninclude a differential case 100, a pair of differential bearings 102, aring gear 104 and a gear set 106. In the particular example provided,the differential case 100 includes a first case member 110 and a secondcase member 112, but those of ordinary skill in the art will appreciatethat the differential case 100 may be unitarily formed or may be formedfrom several case components. The first and second case members 110 and112 can cooperate to define a mounting flange 116, a pair of trunnions118 and a gear cavity 120 into which the gear set 106 can be received.The ring gear 104 can be coupled to the mounting flange 116 via aplurality of threaded fasteners 124. The trunnions 118 can be hollowstructures that can extend from the opposite ends of the differentialcase 100.

The differential bearings 102 can be any type of bearings, such astapered roller bearings, and can include an inner bearing race 130, aplurality of rollers 132, and an outer bearing race 134. The innerbearing race 130 of each differential bearing 102 can be coupled (e.g.,press-fit) to a corresponding one of the trunnions 118. The outerbearing race 134 of each differential bearing 102 can be received in acorresponding one of the differential bearing journals 80 (i.e., betweena bearing cap 56 and an associated one of the bearing journals 72). Inthe example provided, the bearing cap 56 can apply a clamping force tothe outer bearing race 134 that clamps the outer bearing race 134 to thedifferential bearing journal 80.

The gear set 106 can include a pinion shaft 140, which can extendthrough the differential case 100 generally perpendicular to the firstaxis 82, a pair of pinion gears 142, which can be rotatably mounted onthe pinion shaft 140, and a pair of side gears 144 that can be inmeshing engagement with the pinion gears 142. The side gears 144 caninclude an inner diameter having a plurality of spline teeth (notspecifically shown) formed thereon.

The input pinion assembly 36 can be received in the pinion bore 76 inthe carrier housing 54 and can include an input pinion 150 and a pair ofpinion bearings 152. The input pinion 150 can include a pinion portion160, which can be meshingly engaged to the ring gear 104, and a shaftportion 162. The pinion bearings 152 can be tapered roller bearings orangular contact ball bearings having an inner bearing race 164, an outerbearing race 166 and a plurality of rollers 168 disposed between theinner and outer bearing races 164 and 166. The pinion bearings 152 canbe mounted on the shaft portion 162 and coupled to the carrier housing54 to support the input pinion 150 for rotation about a second axis 88that can be perpendicular to the first axis 82.

The axle shafts 38 can be received through the axle tubes 58 and can becoupled for rotation with the side gears 144 (e.g., via mating sets ofspline teeth (not specifically shown) formed on the inside diameter ofthe side gears 144 and the outer diameter of a portion of the axleshafts 38.

During operation of the vehicle 10 (FIG. 1) in a predetermined (e.g.,forward) direction, rotary power is transmitted from the input pinionassembly 36 to the differential assembly 34 to cause the differentialcase 100 to rotate. More specifically, the teeth T of the input pinion150 transmit rotary power to the ring gear 104, causing the ring gear104 (and the differential case 100) to rotate about the second axis 88.As the ring gear 104 rotates, a radially outward portion of it passesthrough the lubricant 90 in the lubricant reservoir 62 and clings to thering gear 104. Due to centrifugal force, a portion of the lubricant thathas clung to the ring gear 104 will be slung from the ring gear 104.

With specific reference to FIG. 4, the first oil gallery 64 can includea first, open end 200 that can be shaped and positioned so as to collectlubricant 90 that has been slung from the ring gear 104. For example,the first open end 200 can have a frusto-conical shape that facilitatescollection of slung lubricant 90. The collected lubricant may be slungdirectly into the open end 200 of the first oil gallery 64 as depictedby the arrows A, and/or could initially collect on the wall member 70 ofthe carrier housing 54 and drain into the open end 200. A second,opposite end 206 of the first oil gallery 64 can terminate adjacent thepinion bearings 152. Each of the pinion bearings 152, which can be atapered roller bearing, can include a plurality of rollers 168 whoseaxes 210 can diverge outwardly from the second axis 88 with increasingdistance from the other one of the pinion bearings 152. The lubricant 90directed to a first side 212 of the pinion bearings 152 can be receivedbetween the rollers 168 and due to centrifugal force, can be directedout of a second, opposite side 214 of the pinion bearings 152. It willbe appreciated that structures, such as seals or baffles, can beemployed inhibit or limit the flow of lubricant 90 exiting the secondside 214 of the pinion bearings 152 in a desired manner. In theparticular example provided, a generally flat plate structure 218 isfitted about the pinion shaft 140 and received in the carrier housing 54to urge the lubricant 90 that exits the second side 214 of the pinionbearings 152 to be received into a first end 230 of the second oilgalleries 66.

With specific reference to FIG. 3, each of the second oil galleries 66can extend from the first end 230, which is proximate the second side214 of the pinion bearings 152, to a second end 216 that can beproximate an associated one of the differential bearings 102. Therollers 132 of the differential bearings 102 can be arranged such thattheir axes 240 diverge from the first axis 82 with decreasing distancetoward an opposite one of the differential bearings 102. Accordingly,lubricant 90 discharged from the second oil galleries 66 proximate afirst side 250 of the differential bearings 102 can be received betweenthe rollers 132 and discharged from a second side 252 of thedifferential bearings 102. It will be appreciated that some portion ofthe lubricant 90 discharged from the second side 252 of the differentialbearings 102 can be received through one or more apertures 260 in thedifferential case 100 that can permit lubricant 90 to be received intothe gear cavity 120 to facilitate lubrication of the gear set 106.

It will be appreciated that third oil galleries (not specifically shown)could be coupled in fluid communication to the first oil gallery 64and/or second oil gallery 66 to distribute a portion of the lubricant 90received into the first oil gallery 64 into openings (not specificallyshown) in the carrier housing 54 so that such lubricant 90 can bereceived into the axle tubes 58. The lubricant 90 that is received intothe axle tubes 58 can be employed to lubricate wheel bearings and seals,as well as to reject heat to the axle tubes to thereby aid in thecooling of the lubricant 90.

While the second oil galleries 66 have been illustrated as being fedlubricant from the one of the pinion bearings 152 that is closest to theteeth T of the input pinion 150 (i.e., the head bearing), it will beappreciated that the second oil galleries 66 could be fed lubricant fromthe other one of the pinion bearings 152 (i.e., the tail bearing, whichis axially further from the teeth T of the input pinion 150) as shown inFIG. 3A. It will also be appreciated that a first one of the second oilgalleries 66 could be fed from a first one of the pinion bearings 152and the other one of the second oil galleries 66 could be fed from asecond, different one of the pinion bearings 152 as shown in FIG. 3B.

While the axle assembly 22 has been illustrated and described asincluding a carrier housing 54 having enclosed conduits (i.e., thesecond oil galleries 66′) that are integrally formed therewith (e.g.,formed with the carrier housing 54 when the carrier housing 54 is cast),those of ordinary skill in the art will appreciate that an axle assemblyconstructed in accordance with the teachings of the present disclosuremay be formed somewhat differently. For example, the conduits (i.e., thesecond oil galleries 66′) can be formed separately from the carrierhousing 54 and can be assembled thereto. As another example, the secondoil galleries 66′ may include one or more open channels 600 asillustrated in FIGS. 5 and 6. In the example illustrated, the carrierhousing 54′ is constructed such that the wall member 70′ includes one ormore interior walls or rails 604 that slope toward the bearing journals72′. The rails 604 can have an exterior surface with any desired shape,such as an arcuate channel shape into which lubricant can collect. Afeed aperture 610 can be formed through each of the bearing journals 72′to permit lubricant to flow from an associated one of the rails 604 tothe differential bearings (not specifically shown). The lubricant can bedirected to the rails 604 in several ways. For example, the second oilgalleries 66′ can include a conduit portion 620 that can be integrallyformed with the carrier housing 54′. The conduit portion 620 can receivelubricant from the second side of the differential bearings as describedabove and can discharge the lubricant to one or more of the rails 604.Additionally or alternatively, splash lubrication can be employed todeposit lubricant on the rails 604. Such splash lubrication could employlubrication slung from the ring gear 104 and/or lubricant exiting thesecond side of the pinion bearings (as described above) that is receivedonto (and slung from) the pinion portion 150 as illustrated in FIGS. 7and 8. In this example, oil slung from the ring gear 104 and the pinionportion 160 is deposited directly onto the rails 604 of the second oilgalleries 66″, which are integrally formed with the carrier housing 54″.

While specific examples have been described in the specification andillustrated in the drawings, it will be understood by those of ordinaryskill in the art that various changes may be made and equivalents may besubstituted for elements thereof without departing from the scope of thepresent disclosure as defined in the claims. Furthermore, the mixing andmatching of features, elements and/or functions between various examplesis expressly contemplated herein so that one of ordinary skill in theart would appreciate from this disclosure that features, elements and/orfunctions of one example may be incorporated into another example asappropriate, unless described otherwise, above. Moreover, manymodifications may be made to adapt a particular situation or material tothe teachings of the present disclosure without departing from theessential scope thereof. Therefore, it is intended that the presentdisclosure not be limited to the particular examples illustrated by thedrawings and described in the specification as the best mode presentlycontemplated for carrying out the teachings of the present disclosure,but that the scope of the present disclosure will include anyembodiments falling within the foregoing description and the appendedclaims.

1. An axle assembly comprising: a carrier housing assembly that definesa cavity; a differential housing received in the cavity; first andsecond bearings disposed between the carrier housing and thedifferential housing, the first and second bearings being tapered rollerbearings and supporting the differential housing for rotation about afirst axis; a gearset received in the differential housing; a ring gearcoupled to the differential housing; a pinion received in the cavity,the pinion having a plurality of teeth that are meshingly engaged to thering gear; a third bearing disposed between the carrier housing and thepinion, the third bearing supporting the pinion for rotation about asecond axis that is perpendicular to the first axis; and a lubricantreceived in the cavity; wherein the carrier housing includes at leastone of a first lubricant gallery, which extends from the third bearingto a first side of the first bearing, and a second lubricant gallerythat extends from the third bearing to a first side of the secondbearing, the first and second bearings being oriented to receivelubricant from the first and second lubricant galleries, respectively;wherein the lubricant received by the first bearing is moved through thefirst bearing toward the second bearing when the axle assembly isoperated; and wherein the lubricant received by the second bearing ismoved through the second bearing toward the first bearing when the axleassembly is operated.
 2. The axle assembly of claim 1, wherein thedifferential housing includes first and second openings that areconfigured to receive at least a portion of the lubricant that isdischarged from the second side of the first and second bearings.
 3. Theaxle assembly of claim 1, wherein the first lubricant gallery isintegrally formed with the carrier housing.
 4. The axle assembly ofclaim 3, wherein the second lubricant gallery is integrally formed withthe carrier housing.
 5. The axle assembly of claim 1, further comprisinga fourth bearing disposed between the carrier housing and the pinion,the fourth bearing supporting the pinion for rotation about the secondaxis, the fourth bearing being disposed axially closer to the teeth ofthe pinion than the third bearing.
 6. The axle assembly of claim 1,further comprising a fourth bearing disposed between the carrier housingand the pinion, the fourth bearing supporting the pinion for rotationabout the second axis, the fourth bearing being disposed axially furtherfrom the teeth of the pinion than the third bearing.
 7. The axleassembly of claim 1, wherein the third bearing is a tapered rollerbearing or an angular contact ball bearing.
 8. An axle assemblycomprising: a carrier housing assembly that defines a cavity; adifferential housing received in the cavity; first and second bearingsdisposed between the carrier housing and the differential housing, thefirst and second bearings being tapered roller bearing and supportingthe differential housing for rotation about a first axis; a gearsetreceived in the differential housing; a ring gear coupled to thedifferential housing; a pinion received in the cavity, the pinion havinga plurality of teeth that are meshingly engaged to the ring gear; athird bearing disposed between the carrier housing and the pinion, thethird bearing supporting the pinion for rotation about a second axisthat is perpendicular to the first axis; a fourth bearing disposedbetween the carrier housing and the pinion, the fourth bearingsupporting the pinion for rotation about the second axis, the fourthbearing being disposed axially closer to the teeth of the pinion thanthe third bearing; and a lubricant received in the cavity; wherein thecarrier housing includes at least one of a first lubricant gallery,which extends from one of the third bearing and the fourth bearing to afirst side of the first bearing, and a second lubricant gallery thatextends from one of the third bearing and the fourth bearing to a firstside of the second bearing, the first and second bearings being orientedto receive lubricant from the first and second lubricant galleries,respectively; wherein the lubricant received by the first bearing ismoved through the first bearing toward the second bearing when the axleassembly is operated; and wherein the lubricant received by the secondbearing is moved through the second bearing toward the first bearingwhen the axle assembly is operated.
 9. The axle assembly of claim 8,wherein both the first and second lubricant galleries are fed lubricantdirectly from the third bearing.
 10. The axle assembly of claim 8,wherein both the first and second lubricant galleries are fed lubricantdirectly from the fourth bearing.
 11. The axle assembly of claim 8,wherein the first and second lubricant galleries are fed lubricantdirectly from different ones of the third and fourth bearings.
 12. Theaxle assembly of claim 8, wherein the third bearing is a tapered rollerbearing or an angular contact ball bearing.
 13. A method for lubricatingan axle assembly comprising: providing a carrier housing, a differentialhousing, first and second bearings, a gearset, a ring gear, a pinion,and a third bearing, the carrier housing assembly that defining acavity, the differential housing being received in the cavity, the firstand second bearings being disposed between the carrier housing and thedifferential housing, the first and second bearings being tapered rollerbearings and supporting the differential housing for rotation about afirst axis, the gearset being received in the differential housing, thering gear coupled to the differential housing, the pinion received inthe cavity, the third bearing disposed between the carrier housing andthe pinion and supporting the pinion for rotation about a second axisthat is perpendicular to the first axis; rotating a portion of the thirdbearing relative to a remaining portion to pump a lubricant throughfirst and second lubricant galleries associated with the carrier housingto supply the lubricant to the first and second bearings, respectively;and rotating a portion of the first and second bearings relative torespective remaining portions to pump the lubricant through the firstand second bearings.
 14. An axle assembly comprising: a carrier housingassembly that defines a cavity and a pair of bearing journals; adifferential housing received in the cavity; first and second bearingsdisposed between the carrier housing and the differential housing, thefirst and second bearings being tapered roller bearings and supportingthe differential housing for rotation about a first axis; a gearsetreceived in the differential housing; a ring gear coupled to thedifferential housing; a pinion received in the cavity; a third bearingdisposed between the carrier housing and the pinion, the third bearingsupporting the pinion for rotation about a second axis that isperpendicular to the first axis; and a lubricant received in the cavity;wherein the carrier housing defines a plurality of rails that slopetoward the bearing journals, wherein a portion of the lubricant isprovided to the rails (a) after it is discharged from the third bearing,(b) after being slung from the ring gear, (c) after being slung from thepinion, or (d) a combination of two or more thereof.